misssing on more than one cylinder?

[toywilly]

I am having trouble getting my 2f to run right. It seems that the last three cylinders ie 4, 5, and 6 are not firing. The strange thing is that if I remove either of these three plug wires the iddle seems to increase and the motor smoothes out. also if I advance the timing a lot the motor will run better. Is it possible I am completey out of time or have a hooked something up wrong. All the plug wires are on the correct plug and the valves have been set properly. good comp on all cylinders and I put a new cap and rotor on a few weeks ago and replaced ALL the vac lines, even rebuilt the carb. I had it running awsome at 650rpm in the driveway and then took it out for a spin, about 3 miles. just as I returned home it started to sputter and stalled out. one more thing is I put a brand new cat on it last week. thanks for any help

 

[gaylon]

to get the discussion started...

Since you did all that work, I would spend a good bit of time verifying everything you did. When I do a lot of work and a problem develops soon after it is pretty much always something I screwed up. I would first ensure that the vac lines are hooked up correctly. It is a good evolution to change all the vacuum lines out, but the chances of hooking them up incorrectly, putting a check valve in backwards, etc. is high enough that I would go over all hoses and their locations again. Double check all the check valves are working and installed in the correct direction. Pull the PCV and see of the suction that is supposed to be present is.

Was is a new cap, if not ensure there is no corrosion on the contacts. Then go over the spark plug wires one by one. Verify they each have spark. Pull the plugs to ensure they are not fouled at all.

I know this seems relatively elementary, but I often find the problem is the result of my own handiwork and a good objective review of the work finds the issue.

Now, assuming you are getting good fuel flow (which I have no reason to assume other than that removing a plug wire should not improve the situation if the fuel is restricted), the carb rebuild is a pretty significant job. There is a fair chance something is slightly off. I am not carb expert, so I will leave that to the others...

 

[chitown40]

Did you have the distributor out at all?

 

[toywilly]

the dristributer did not come out and the cap is brand new. I ohmed all the wires and there within specs per FSM. I am def getting spark on on all the plugs. I cannot figure out why the engine would run smoother with any of the three plug wires removed. Im thinking it has to be vac related but Im new to the cruizer thing and not sure if vac would effect the engine this strongly.

 

[Droopynut]

check the fuel lines under the truck for corrosion. especially near the top of the gas tank (inlet/outlet lines). They rust out and the fuel pump sucks the rusty metal flakes into the carb causing issues.

 

[rchalmers3]

I am having trouble getting my 2f to run right. It seems that the last three cylinders ie 4, 5, and 6 are not firing. The strange thing is that if I remove either of these three plug wires the iddle seems to increase and the motor smoothes out. also if I advance the timing a lot the motor will run better. Is it possible I am completey out of time or have a hooked something up wrong. All the plug wires are on the correct plug and the valves have been set properly. good comp on all cylinders and I put a new cap and rotor on a few weeks ago and replaced ALL the vac lines, even rebuilt the carb. I had it running awsome at 650rpm in the driveway and then took it out for a spin, about 3 miles. just as I returned home it started to sputter and stalled out. one more thing is I put a brand new cat on it last week. thanks for any help

As I recall, the symptom of having the RPM's rise when you deaden a cylinder can come from 2 things: Incorrect firing order or blown head gasket where the flame from one cylinder leaks into an adjoining cylinder.

I doubt it's the latter, so have another pair of eyes check your tune-up work. I think it's the firing order.....

Rick

 

[HighPlainsDrifter]

x2 Check the plug wires.

 

[D'Animal]

Since it seems you have a proplem when it warms up, check you BSVSBTVQRST valves.

 

[toywilly]

Since it seems you have a proplem when it warms up, check you BSVSBTVQRST valves.

ellaborate please

 

[rchalmers3]

Since it seems you have a proplem when it warms up, check you BSVSBTVQRST valves.

Go ahead: Whip out the Campbell's alphabet soup on the poor guy!

Rick

 

[toywilly]

upon further investigation it appears to only be 5 and 6 not firing. If I leave them both disconected the truck idles. once I hook em up it dies. of to search I guess.

 

[D'Animal]

VSV = Vacuum switching valves.

I think the FSM calls them BSVSV valves. Bull Sheit vacuum Switching Valves.

There are blue ones up by your thermostat and green ones by your distibutor. There are a few more that screw into the thermo housing, ect.

 

[rchalmers3]

upon further investigation it appears to only be 5 and 6 not firing. If I leave them both disconected the truck idles. once I hook em up it dies. of to search I guess.

Did you swap the wires on the 2 dead cylinders while it's running to confirm proper firing order sequence?

Now you may want to perform a compression test to see if there's a breach in the haed gasket allowing gasses to pass between those affected cylinders. Those two cylinders will be low on compression relative to the other 4.

If the gasket is blown, the flame and expansion that's supposed to be happening in one cylinder leaks into the adjoining cylinder when the piston is rising, effectively putting the brakes on the crank! It is a real possibility now that you have identified a pair of cylinders that are not working.

Rick

 

[toywilly]

ill recheck the compression when I get home. I cant believe that the head gasket would have blown so fast. its only two weeks old with maybe 10 miles on the motor since the head went back on. well see i guess

 

[gaylon]

ill recheck the compression when I get home. I cant believe that the head gasket would have blown so fast. its only two weeks old with maybe 10 miles on the motor since the head went back on. well see i guess

You did not mention before that the head was recently replaced. Was it cleaned and machined properly? Were the valves adjusted properly? Improperly adjusted valves could be causing failed compression, also.

 

[toywilly]

yeah it was done right. Had all the exhasut valves replaced and the head resurfaced, took .050 off. The valves have been adjusted a few times to ensure they are within specs. I am just now realizing people have been having trouble with the aftermarket head gaskets. I hope it isnt blown already.

 

[krzyabncanuck]

There are certain things you never want to go cheap on, and that is one of them. Kinda like the timing chain in a 20 / 22R.

 

[toywilly]

took compression 140 psi across the board. I am lost at this point. I cannot figure out why hooking 5 and 6 up will kill the motor. Is it possible for the head gasket to be blown without affecting compression?

 

[CruisinFJ60]

There are certain things you never want to go cheap on, and that is one of them. Kinda like the timing chain in a 20 / 22R.

or get ya a double roller
look cool and effective

 

[iaintscared1969]

Just for the sake of doing it. Put the truck on TDC and check where your rotor is pointing. If you were slightly off on the timing would cause it. Just eliminating as I go through it. I have had trucks come to me running. Do a tune up,valves,and wires, and have it run light crap. Then check the timing and realize they had it timed wrong.